If you double-check something, you examine or test it a second time to make sure that it is completely correct or safe. Check and double-check spelling and punctuation Double-check that the ladder is secure Don't believe what you are told; double-check with an independent source. to check something again so that you are completely sure it is correct, safe etc
A discovered check wherein the both the moved piece and the revealed piece give check simultaneously The only way to escape a double check is for the King to move